Pretty disappointed in this kit. I have used a couple of the different coils successfully but the coils that I was most excited about were the Tri-Core Fused Claptons. These are specified as .21 ohms but in reality as measured in a CoilMaster 521 mini as well as my Smok Alien they measure .17. Some variation between spec'd and actual is certainly acceptable but in parallel these measure .9 ohms and will not pre-fire in the CoilMaster, don't know if the Alien can handle this but not really interested in finding out. So the good news is that I have several usable coils for pretty short dollars but 6 coils that are pretty much unusable.